NGC 6500/6501 supernova SN 2021wuf

[Martin Meredith]

Alerted to this by a post by Steve Gottlieb, I had a quick look last night at this fairly bright SN in Hercules. The SN is the bright object more or less equidistant from the two galaxies and just off a line joining their cores. Compare with the DSS shot and the SN is obvious. It seems to be of a similar magnitude to one of the companion stars listed as GAIA g-mag 14.6. Here's the discovery info (23 Aug). 

NGC 6500 is a type Sab spiral while NGC 6501 is type S0-a. They lie at 150 +/- 3 MLyrs.

As Steve points out, it isn't clear which galaxy this should be assigned to. With the stretch turned up (lower right inset) NGC 6500 appears to have a spiral arm curving upwards and clockwise, with the SN lying near the tip (or perhaps this is just a visual suggestion -- there is an arm there as the DSS image shows, but whether it continues upwards is open to question).

The bright star at the left of the image is the double Struve 2245 with a sep of 2.7". The position angle is 116 which is manifest in my shot by a slight ellipsoid bulge in the ENE direction and a hint of a kidney shape (2.7" is less than 1.5 pixels on my sensor...). The companion star is also pretty bright, at mag 7.5.

There is a strange piece of galactic? fluff due north of the double star. It isn't an artefact of the bright star as it also appears in the same location on the DSS image. Apart from being very blue, I haven't been able to find out more about it -- perhaps an irregular galaxy?

Martin

Edited September 9, 2021 by Martin Meredith

[RobertI]

Nice capture Martin and very interesting analysis. I think you're right about the galactic fluff - reminds me of Mirach's Ghost.

[mdstuart]

Lovely image. I saw those galaxies back in 2011 in a 10 inch dob. I will go back again with my big dob.

Mark

[Mike JW]

Hi Martin,

Last night I took a look at the SN with the 15 but the shots do not add to your image. I tried 5, 10 and 15 sec subs but I could not get any evidence of the possible arm leading to the SN.  I love the term galactic fluff and further to the left of the double star is another galaxy with no info. The double star intrigued me - would it be possible to actually show it is a double using my set up - see below. The shot is just 1 sub and linear setting.

 

Mike

 

Edited September 10, 2021 by Mike JW

[Martin Meredith]

Thanks Rob and Mark.

Mike, I looked at a few other sky surveys via Aladin and also could find no hint of the arm. Nice work on the double! Very clear separation. I might add a position angle/separation measure tool at some point.

Martin